Thermal transfer recording medium

Abstract

A thermal recording medium has two or more kinds of thermo sensitive ink on a base member thereof, and each of the inks has a different melting point and a different color. At least one of the inks also contains an achromatizing agent for concealing a color of at least one of the inks. The thermal transfer recording medium thus constructed is capable of producing multiple colors on a recording sheet by utilizing a device having only one heating head.

What is claimed is: 
     
       1. A thermal transfer recording medium having a base member, comprising: at least two kinds of thermo sensitive ink having different melting points applied to said base member in a mosaic form, and an achromatizing agent contained in at least one of said two or more kinds of thermo sensitive ink, said achromatizing agent being adapted to conceal a desired color when said recording medium is heated to a predetermined temperature.   
     
     
       2. The thermal sensitive recording medium claimed in claim 1 wherein said at least two or more kinds of thermo sensitive ink have different colors. 
     
     
       3. The thermal recording medium claimed in claim 2 wherein said achromatizing agent comprises a discoloring agent. 
     
     
       4. The thermal transfer recording medium claimed in claim 1, 2 or 3 wherein said thermal sensitive inks comprise first, second, third, fourth and fifth inks having melting temperatures T1, T2, T4, T6, and T7 respectively and having predetermined colors, said first ink having an achromatizing agent adapted to conceal said color of said second ink at a temperature between said temperature T2 and T4, said second ink having an achromatizing agent adapted to conceal said color of said third ink at a temperature T5 between said temperature T4 and T6, said third and fourth inks having an achromatizing agent adapted to conceal said third and fourth ink colors respectively at a temperature T8 which is above said temperature T7. 
     
     
       5. The thermal transfer recording medium claimed in claim 4 wherein said first, second, third, fourth and fifth ink colors comprise cyan, magenta, yellow, cyan and black, respectively. 
     
     
       6. A thermal recording medium of the type having at least one layer of thermo sensitive ink having a transfer surface for contacting and transferring ink to a recording sheet or the like, said layer comprising at least two kinds of different thermo sensitive inks having different colors and different respective melting points, said two kinds of thermo sensitive inks being exposed at different respective regions of said transfer surface. 
     
     
       7. The thermal recording medium claimed in claim 6 wherein said kinds of thermal sensitive ink each comprise a binder, a color producing material, and a softner. 
     
     
       8. A thermal recording medium as claimed in claim 6, wherein said at least one layer comprises a mosaic pattern of said at least two kinds of thermo sensitive inks.